In many cellulose plants, the cellulose-drying machine is a bottleneck in production, so that special attention is paid to its operation. In accordance with the present technique, the blades of the cross-cutting roller of the sheet cutter of the drying machine are changed every two months, sometimes even every two weeks if necessary. The blunt blades are generally sent to a suitable manufacturer for sharpening, after which they are returned to the plant. The removal of the blade sheets of the cross-cutting roller and their replacement with other blades causes a shutdown of about eight hours in the production of the entire plant. Naturally, attempts are made to fit this in with other breaks in production, but this does not always succeed, or the change of the blades prolongs shut-down from other causes.
Blades that have been removed can be sharpened for example in a sharpening device in accordance with U.S. Pat. No. 4,685,250. British patent publication GB-1432873 shows a sharpening device that is intended to sharpen the blades of cylinder rollers, in particular in grain and hay harvesters. A device of this kind requires the previous installation of suitable guides on the frame of the machine, in which the grinding device can move. Devices of this kind are difficult to adapt to suit the sheet cutter of a drying machine, because its width, 6-8 m, would lead to massive support structures.
German publication print 1159804 describes a sharpening device for the blade of a planing machine, in which the sharpening device is placed on top of the drum by means of sliding shoes located on both sides of the blade. A solution of this kind cannot be considered with long blades, because the surface of the drum is in any case so uneven that a good support cannot be obtained from it.